| 摘要 |
PURPOSE:To obtain a waveform conversion circuit featuring the steady operation by excluding the capacitor which is hard to be formed as the semiconductor element within the semiconductor integrated circuit. CONSTITUTION:The intermediate-frequency signal sent from intermediate-frequency filter 24 is applied to terminal 1' and then converted into the rectangular wave signal featuring the complementary relation through amplitude limiter 1 to be amplified by differential amplifier 2. The trapezoid wave signal is produced via charging circuit 3a, discharging circuit 3b and capacitor C2 and with use of the amplified signal of one side. In the same way, the rectangular wave signal is produced through waveform shaping circuit 4. These two signals receive the regulation of the amplitude level through constant voltage circuit 5 plus 1st and 2nd voltage limit circuits 6 and 7 each. After this, the two trapezoid wave signals of different amplitude levels are produced from the trapezoid wave signal through 1st level shift circuit 9. In the same way, the two rectangular wave signals of different amplitude levels are produced in the same way through 2nd level shift circuit 10. These trapezoid and rectangular wave signals are supplied to voltage comparator circuit 11, and thus the pulse signal of the fixed duration is produced at the zero-level crossing position of the intermediate-frequency signal. |
